[math-fun] Prove it's defined?

n(x):= the largest n s.t. binom(n,2) has no prime divisor >x. Apparently x n(x) 2 2 3 9 5 16 7 4375 11 9801 13 9801 17 336141 19 11859211 23 11859211 29 18085705 31 370256250 37 370256250 41 45105689161 These are highly untrustworthy, but at least suggestive. (Should they all be square??) Anybody know more? (Ditto for n^2-1 instead of binom(n,2).) --rwg ON ONE'S TOES NOSE TO NOSE ALGORISMIC MICROGLIAS